1.Field of the Invention
The present invention relates to an exhaust apparatus including a vacuum pump.
2.Description of the Related Art
In recent years, there is a demand for, for example, semiconductor devices to be more precise and accurate. In satisfying this demand, one task is to reduce the influence of gas molecules and particles existing in the atmosphere in a manufacturing step, such as an exposure step.
These particles and gas molecules and compounds thereof adhere to the interior of an apparatus or to a processing object, thereby reducing the performance of the apparatus and the quality of a product. If confined to semiconductor exposure apparatuses, light having short wavelengths, as typified by EUV (extreme ultraviolet) light, is considerably attenuated in the atmosphere, thereby making it difficult to obtain a predetermined light quantity.
To solve these various problems, research of ultrafine processing under a high vacuum environment has been conducted. If the interior of a vessel is set to a highly vacuous state, the number of particles or molecules existing in the atmosphere is relatively small. Therefore, the amount of contaminant adhered to the interior of the apparatus and the processing object is reduced. In addition, since the transmittance of the light having short wavelengths is considerably increased, light having extremely short wavelengths, such as EUV light, can be used.
In a device manufacturing step such as that described above, thermal deformation of a manufacturing apparatus and the processing object influences the quality of the product. Therefore, a temperature control technology becomes important. For example, for an exposure apparatus using EUV light, when the temperature varies due to transfer of heat by, for example, radiation, optical performance may be reduced due to deformation of an optical element (such as a mirror), a member holding the optical element, etc. Therefore, in vacuum vessels including heat sources related to quadrupole mass analyzers or other measuring devices or vacuum pumps (such as turbo molecular pumps), reducing the influence of heat is very important.
Under a high vacuum environment, temperature control making use of convection of heat as in atmospheric environment cannot be performed. Movement of heat is dominated by conduction and radiation. In particular, regarding radiation, since heat is also transferred to an object that is separated through a space, it is desirable that the influence of this heat be reduced.
For intercepting the radiation of heat from a heat source, providing an intercepting member that intercepts the radiation from the heat source is known (Japanese Patent Laid-Open No. 2005-020009). Japanese Patent Laid-Open No. 2005-020009 discusses performing an exhaust operation while intercepting the radiation of heat through a louver in order to reduce the influence of the radiation of heat from a vacuum pump.
The heat radiation intercepting member discussed in Japanese Patent Laid-Open No. 2005-020009 is such that an exhaust path forming the louver is bent and has a shape allowing it to shield the vacuum pump when expected from a side facing the vacuum pump. That is, the intercepting member whose exhaust path is bent can perform the exhaust operation while intercepting the radiation of heat moving straight from the vacuum pump. However, since the exhaust path is bent, particles and gas molecules collide at least once with a surface of the intercepting member. Therefore, the intercepting member discussed in Japanese Patent Laid-Open No. 2005-020009 is not desirable in terms of exhaust efficiency.